A plastic secondary cell made of electrodes of a plastic material such as polyacetylene which becomes highly electrically conductive when it is doped with ions, and an organic electrolyte containing (n-Bu.sub.4 N)ClO.sub.4 or LiI as the electrolytic substance, is now drawing attention owing to its advantages such as its large charge/discharge capacity per unit weight, its lack of dendritic deposition while it is being charged, and its light weight. At the moment, however, such a secondary cell having a satisfactory cell performance has not yet been developed and, hence, has not been, put to practical use.